Mechanically Adjustable Inflow Control Device

ABSTRACT

An adjustable inflow control device features a mechanically rotatable sleeve that advances or retreats axially when rotated in opposed directions to cover or uncover a labyrinth flow path from an inlet to an outlet. When used for inflow the outlet is into a tubular string to a surface location. The more the sleeve is retracted away from the labyrinth path the less resistance to flow is offered and vice versa. Another way to mechanically alter the flow resistance is to have an outer housing with a spiral groove and an axially movable inner mandrel with another spiral groove. The mandrel can be axially advanced with rotation when connected with a thread. Advancing the mandrel so that there is more overlap between the spiral patterns increases resistance to a give flow rate and vice versa. A gap between the mandrel and housing allows the mandrel to rotate and translate.

FIELD OF THE INVENTION

The field of the invention is inflow control devices for borehole use and more particularly devices that are mechanically adjustable when downhole to balance flow from or into a formation.

BACKGROUND OF THE INVENTION

Various types of flow devices are used in the production of hydrocarbons. One common surface mounted device is a choke which is a multi-position valve operated manually or with a motor at a surface location to control flow to the surface from a formation. Another type of flow control for boreholes is a system of flow balancing using a plurality of spaced inlets that feature a tortuous flow path with the devices closest to the surface configured before running in to have more resistance to flow than devices on the same string further from the surface. While incremental resistance in the tubular string for a given flow rate is reliably calculated in advance there are other variables such as formation pressures and porosities that make flow balancing with non-adjustable inflow control devices ahead of time much more difficult. Flow balancing is also important in operations such as gravel packing for uniform gravel distribution around a series of spaced apart screens.

Inflow control devices (ICD) commonly feature a tortuous path from an annulus inlet to a tubing side outlet to direct flow from the formation to the surface. Injection service reverses the flow direction but the objective remains the same, balancing flow. In some designs a spiral path for the fluid is induced with stationary vanes with the idea that if the properties of the produced fluid change primarily in viscosity a different flow regime will ensue without moving any parts. A design of this type is shown in U.S. Pat. No. 8,376,047. Other designs feature multiple fluid inlets with each configured with variable diodes where the paths are defined within an outer shroud as described in US 2015/0337622. This design would entail delivered or stored electric power which can add expense and operational issues. Another design involves stackable rings with passages that have flow resistors that can be stacked in advance of running in to quickly get the degree of flow resistance desired at each location. This is described in US 2013/0206245.

References have suggested restriction variability downhole using stepper or other types of motors to change flow resistance. One example is U.S. Pat. No. 8,204,693 item 81 and another using a motor driven selector plate is U.S. Pat. No. 8,267,180 items 12 and 14. Regulation of gas lift flow is taught in U.S. Pat. No. 5,937,945 using a helical surface advanced toward and away from a similarly shaped seat to change resistance to flow while the devices are mounted in the borehole. U.S. Pat. No. 7,789,145 teaches a shifting tool to engage the ICD and axially shift a sleeve with collet fingers from one profile groove to another to change the resistance to flow. This reference mentions multiple stop positions between least and most resistance to flow. Such a tool is expensive to manufacture and may not give sufficient feedback that it has shifted sufficiently or worse still it may skip the desired collet locating groove to an adjacent groove in which case the resistance to flow may change more than desired in either direction.

Using variable ICDs that require electric power creates difficulties in the space that power devices take up or the need to deliver power from a remote source. Operational reliability issues can spring up. What is offered is mechanically adjustable designs that vary the resistance to flow. One way is by using a thread mounted sleeve whose rotation covers or uncovers a labyrinth passage so as to short circuit some of the labyrinth by uncovering it when the sleeve is retracted and to increase the flow resistance if the sleeve moves in an opposite direction. In another variation the labyrinth path can be spiral with part of the path on a stationary outer sleeve and the remainder of the path on a movable sleeve. Axial movement of the movable sleeve can lengthen or shorten the number of overlapping spiral paths so as to change the resistance to a given flow rate. The inner member can be advanced with rotation about a threaded connection. The spiral paths in the two members have a clearance in between. Thus as more spirals overlap there is more resistance to flow and vice versa. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while understanding that the full scope of the invention is to be determined from the appended claims.

SUMMARY OF THE INVENTION

An adjustable inflow control device features a mechanically rotatable sleeve that advances or retreats axially when rotated in opposed directions to cover or uncover a labyrinth flow path from an inlet to an outlet. When used for inflow the outlet is into a tubular string to a surface location. The more the sleeve is retracted away from the labyrinth path the less resistance to flow is offered and vice versa. Another way to mechanically alter the flow resistance is to have an outer housing with a spiral groove and an axially movable inner mandrel with another spiral groove. The mandrel can be axially advanced with rotation when connected with a thread. Advancing the mandrel so that there is more overlap between the spiral patterns increases resistance to a give flow rate and vice versa. A gap between the mandrel and housing allows the mandrel to rotate and translate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic section view of an axially movable sleeve whose movements can lengthen or shorten the length of a labyrinth path;

FIG. 2 is the view of FIG. 1 with the inflow control device in the minimal or no flow condition;

FIG. 3 is the view of FIG. 2 with the inflow control device in a medium resistance to flow position;

FIG. 4 is the view of FIG. 3 with the inflow control device in the position of least resistance to flow;

FIG. 5 is a schematic view of an internally movable mandrel with a matching thread pattern to an outer housing where the amount of thread overlap determines resistance to flow;

FIG. 6 is a section view of the stationary outer housing showing maximum thread overlap from the mandrel inside;

FIG. 7 is the view of FIG. 6 with less thread overlap between the mandrel thread and the surrounding housing thread;

FIG. 8 shows a rolled flat view of the mandrel thread fully engaged with the surrounding housing thread;

FIG. 9 is the view of FIG. 8 with less overlap;

FIG. 10 is the view of FIG. 9 with no overlap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a tubular string 10 that can have multiple inflow control devices (ICD) 12 although only one is shown. When used together the ICDs 12 balance the flow from a formation or in the other direction an injection rate into the formation for a treatment. Typically, the ICD 12 has an inlet 14 in an annulus 16 and a schematically illustrated tortuous path 18 that starts at inlet 14 and ends at an opposite outlet end 20. An internal sleeve or member 22 has an end thread 24 that is engaged to an internal end thread 26 on housing 28 that also has inlet 14 through it and continues to cover the labyrinth path 18. A seal 30 that can be mounted to the sleeve 22 or the inside wall of the tubing string 10 can optionally be used so that in the FIG. 1 position of sleeve 22, the gap 32 between sleeve 22 and the inside wall of the string 10 is closed. Movement of the sleeve 22 in the direction of arrow 34 opens gap 32 by defeating the seal 30. As the sleeve 22 moves further axially in the direction of arrow 34 end 36 overlaps the labyrinth path less and less effectively shortening the length of the labyrinth and hence resistance to a given flow rate. This is graphically illustrated in FIGS. 2-4 where the labyrinth 18 overlap by the sleeve 22 progressively decreases. The housing 28 is omitted from FIGS. 2-4 to assist in making this point. In essence the incoming flow will run to the end 36 of the sleeve 22 and then as shown schematically by arrow 38 the remainder of the labyrinth 18 is simply bypassed as the flow has direct access into the string 10 in a situation where the service is inflow control. Thus in FIG. 4 part of the labyrinth 18 is traversed where in FIG. 3 almost all of the labyrinth 18 is bypassed.

The axial movement of the sleeve 22 is accomplished by engaging tabs or profiles 40 with a schematically illustrated tool T that can impart a rotational force to the tabs or profiles 40 to advance sleeve 22 axially as it rotates by using engaged threads 24 and 26. Although a thread is illustrated, the shifting tool T can also move the sleeve 22 using a j-slot pattern with progressively longer slots so that the resistance to flow can be incrementally changed mechanically with a series of opposed axial movements to balance flow among locations followed by removal of the tool without there being restrictions to flow in the string 10 that could impede production. As previously described one or more ICDs 12 can be completely shut off or they can all be shut off to stop production of undesired fluids from a part or an entirety of a given formation or to allow operation of tools with pressurizing string 10. Each ICD 12 can have a signal transmitter 44 to communicate with tool T to allow surface personnel to know that tool T has reached a specific ICD 12. Keeping the actuation system for the sleeve 22 mechanical keeps it simple and reliable. Using a thread to induce axial movement of sleeve 22 allows more reliable incremental axial movements to be imparted to the sleeve 22 and it further resists forces from high velocity produced fluid passing through string 10 that could change the position of the sleeve 22 were it only retained by a collet in a groove as in U.S. Pat. No. 7,789,145.

FIG. 5 illustrates a variable ICD 50 that features a housing 52 that has a thread form 54 cut into an inside wall 56. The thread form 56 starts at inlet 58 in the surrounding annulus 60 and terminates at port 62 for access into the string 64. Member or mandrel 66 has a thread form 68 that is less wide than thread form 54 but has the same pitch. What advances mandrel 66 axially as it is rotated is a drive system as described with regard to FIG. 1 but not shown in FIGS. 5-10. This includes the mating threads 24 and 26 or their alternatives as previously described. Thus as mandrel 66 is rotated and axially advanced in the direction of arrow 70 the resistance to flow increases as the overlap of thread forms 54 and 68 increases. Conversely if the mandrel is moved while rotating in the opposite direction from arrow 70 then the flow resistance is decreased. The drive threads such as 24 and 26 maintain the thread form 54 and 68 alignment. Seal 72 schematically illustrates that at full overlap of thread forms 68 and 54 the flow can be closed off into port 62 with the same effect as described above for FIG. 1. FIG. 6 shows a closed position with the optional seal 72. Without the seal 72 there may be some minor leak flow between the thread forms 54 and 68 because the drive system for the mandrel 66 in the form of threads 24 and 26 keeps thread form 68 between the sides of the wider thread form 54. In section the shape of the thread forms can be a quadrilateral or a U-shape or a V-shape to name a few options. FIG. 7 shows less thread form overlap than FIG. 6 to offer lower resistance to flow between inlet 58 and port 62. The same concept is illustrated in a rolled flat mode in FIGS. 8-10. Thread forms 54 and 68 preferably have substantially the same pitch. Driving threads 24 and 26 when used in FIG. 5 would also preferably have the same pitch as thread forms 54 and 68. One of thread forms 54 and 68 can be a spiral flow channel and the other can be a spiral ridge. There can be a continuous spiral gap between them as they overlap. A j-slot mechanism would not be used in FIG. 5 for driving.

The adjustment mechanism for the ICD that is illustrated relies on rotation with a tool T that can optionally send information to the surface to indicate the number of turns applied or the position of sleeve 22 or mandrel 66 with respect to end travel stops representing maximum flow resistance and minimum flow resistance. The use of rotation whether with a thread form or with a j-slot and a rotating sleeve having slots at different lengths also helps to fixate the sleeve 22 or the mandrel 66 against flow induced forces during production of injection. Mandrel 66 is hollow to allow flow from other regions to continue from or to the surface depending on the application. Using rotation to vary the resistance allows for infinite adjustments between closed and the least resistance position. The sleeve 22 or mandrel 66 stays put in service as opposed to collets in a profile that can be prone to displacement which would upset the flow balance among multiple ICDs. Disassembly after use is facilitated as the simplicity of the design allows component replacement with merely undoing a thread.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: 

I claim:
 1. An adjustable flow control device between a tubular string and a surrounding annular space, comprising: a housing having a first port to the annular space and a second spaced apart port to the tubular string; a labyrinth flow path between said first and second ports; a rotatably mounted member in said housing, whereupon rotation of said member changes resistance to a predetermined flow between said ports.
 2. The device of claim 1, wherein: said member translates while rotating.
 3. The device of claim 1, wherein: said member comprises a sleeve.
 4. The device of claim 1, wherein: said member is engaged to said housing for said rotation with a driving thread form.
 5. The device of claim 1, wherein: said member is engaged to said housing with a j-slot mechanism having slots of different lengths.
 6. The device of claim 1, wherein: movement of said member engages a seal between said member and said housing to selectively close flow between said ports.
 7. The device of claim 1, wherein: axial movement of said member varies the length of said labyrinth passage between said ports.
 8. The device of claim 1, wherein: said housing comprises one of a spiral flow channel or spiral ridge on an interior wall thereof.
 9. The device of claim 8, wherein: said member comprises the other of a spiral flow channel or spiral ridge on an exterior wall thereof.
 10. The device of claim 9, wherein: relative rotation between said member and said housing alters overlap between said spiral flow channel and said spiral ridge.
 11. The device of claim 10, wherein: said spiral flow channel and said spiral ridge have the same pitch.
 12. The device of claim 10, wherein: said spiral flow channel and said spiral ridge when overlapping present a continuous spiral gap in between.
 13. The device of claim 10, wherein: a seal engages between said spiral flow channel and said spiral ridge at substantial overlap therebetween.
 14. The device of claim 10, wherein: said member is rotatably driven relative to said housing with a threaded drive connection therebetween.
 15. The device of claim 14, wherein: the pitch of said drive connection is substantially equal to the pitch of said spiral flow channel or said spiral ridge.
 16. The device of claim 1, further comprising: a tool insertable in the tubular string to rotate said member; said member comprises at least one tab or profile adapted to be engaged by a tool advanced in the tubular string.
 17. The device of claim 16, wherein: said member or said housing comprising a signal transmitter to communicate with said tool to communicate to a remote location which member in the tubular string is being rotated. 